SACHS DOLMAR

[barchiolaNJ]

hi all,
i have a sachs engine that came with a plane i bought. i read through this thread looking for info to identify the size of the engine but the letters/numbers molded into the base of the cylinder are different from what has been mentioned so far.
the cylinder has SK1704 molded into the front near the base. the letters S and K are over each other almost like a logo. it also has the tolerance stamp, 'B' just across from the spark plug.
any help would be greatly appreciated.
thanks
bart in NJ

[barchiolaNJ]

looking at the case more closely, it appears to have been orange originally and sprayed silver. the mounting plate is 1/8" aluminum with a hole for a pressure port and the words "pressure tap" followed by "8/32" engraved just below the hole. maybe the pressure tap has 8/32 threads?
this is very interesting to read the thread and have an engine to inspect at the same time.
thanks,
bart

[rcign]

That's a Kolbenschmidt cylinder..
B is the bore size to match a B piston..
Can't remember for sure, the 5.2 and 5.8 had different cylinder manufacturers..You might measure the bore and stroke...
The muffler bolts on the 5.8 are not straight across, most of the others are..
I can check tomorrow in the shop, there are some Sachs cylinders in the boneyard....

[rcign]

If you take the cylinder off you will see some overspray inside...I forgot who was converting these...
TKG remembers...
That's a pressure tap for a smoke muffler...I don't remember the 5.8s having one..Must be a smaller one, could be a 3.1...The 3.2 had a Mahle cylinder, the 3.1 was heavier so the 3.2 became the engine of choice...
I know there's a 3.1 in the shop somewhere...

[barchiolaNJ]

so it's a 5.2 or a 5.8? i thought it was a 4.2.
wouldn't i have to pull the cylinder to measure stroke and bore? are gaskets available to reassemble it with?
thanks so far! i really appreciate it.
it's also got a tillotson carb and CH electronic ignition. the muffler bolts are parallel to the fins. the top and bottom bolts that mount the plate to the back of the case are in parallel lines.

[rcign]

Smaller than 5.2...
Most Sachs cases had non parallel bolts, the top 2 parallel to the cylinder base, the bottom not...
A 4.2 would have a MAHLE cylinder with 49ZN cast into the base..47 Mahle is 3.7, 44 Mahle is a 3.2...
3.1 seems to fit the best, will look tomorrow...
Best bet for a base gasket is some thin gasket paper from the auto supply, that engine is probably 15 years old..UNBREAKABLE in normal airplane use...

[barchiolaNJ]

wow, thanks a lot! i'll look forward to hearing what you come up with.
i'll be on a plane to china tomorrow by mid morning so i'll check in when i get there sunday morning.
thanks again,
bart

[barchiolaNJ]

correction, the bolts that mount the mounting plate to the back are NOT in parallel lines.
reading back through older posts this would appear to be a 5.8, no?
this is interesting in that i've heard stories about how big engines were adapted for rc planes but here i've got one that wasn't so much manufactured by Sachs as it was adapted and still called a Sachs.
very neat stuff,
bart

[barchiolaNJ]

	Quote: Originally Posted by rcign
	That's a Kolbenschmidt cylinder.. B is the bore size to match a B piston.. Can't remember for sure, the 5.2 and 5.8 had different cylinder manufacturers..You might measure the bore and stroke... The muffler bolts on the 5.8 are not straight across, most of the others are.. I can check tomorrow in the shop, there are some Sachs cylinders in the boneyard....

ralph,
i know you're probably pretty busy but did you happen to find a match in your pile of cylinders for the Kolbenschmidt that I've got? i'll pull the cylinder today to measure the bore if you don't think you've got a match over at your place.
thanks!
bart

[rcign]

I found some cyliders, send the numbers again...

[barchiolaNJ]

sure ralph, here you go

the cylinder has SK1704 molded into the front near the base. the letters S and K are over each other almost like a logo

[barchiolaNJ]

ralph,
i pulled the cylinder and it's got a stroke of 1.25" and a bore of about 1.75" for a displacement of about 3.0 cu. in. or 50 cc.
thanks for the help.
i'll have to revise the for sale ad to show the correct info as i thought it was a 4.2.
regards,
bart

[alec taylor]

i have a sachs 5,8 in my tow plane (15 years so far) . it has a bigger prop driver made and uses a single prop bolt. how much counter weight should i start with to smouth out the idle a bit (if possible). the prop hub is about 2 inch dia. alex